section
  h3(id='res.json') res.json([status|body], [body])
  
  p.
    Send a JSON response. This method is identical
    to <code>res.send()</code> when an object or
    array is passed, however it may be used for
    explicit JSON conversion of non-objects (null, undefined, etc),
    though these are technically not valid JSON.

  +js.
    res.json(null)
    res.json({ user: 'tobi' })
    res.json(500, { error: 'message' })
